Statistics Canada plans to experiment with online crowdsourcing to help figure out how much cannabis costs on Canada's street corners, which will aid Ottawa in reaching one of its core goals – crushing the drug's black market – as the federal government ends nearly a century of prohibition next summer.

The federal agency says it will glean such information from PriceOfWeed.com, a private website that asks anonymous customers how much they're paying, and plans to create its own price index modelled on this system. Statscan says it will combine this data with Health Canada's first detailed survey of medical and recreational cannabis users.

But public-health experts say these methods don't provide a complete picture of the illicit trade and contend that community-based studies are needed to follow illegal cannabis users before and after legalization if Ottawa is serious about pricing underground competition out of business.

And time is running out to gather the necessary data, critics say. As Canada gets set to become the world's second national case study on the dangers – and potential benefits – of legal cannabis, Ottawa is trying to create a framework to best measure the effects of this historic policy shift. Uruguay has legalized the recreational sale and use of the drug, but access has been limited and the tiny South American country has a population about a tenth the size of Canada.

Supporters of legalization agree that cannabis has to be priced low enough to undercut retailers on the wrong side of the law, but there are varying estimates to how much black-market cannabis costs.

PriceOfWeed.com currently pegs the average gram of "high quality" dried cannabis at $7.56, based on almost 10,000 submissions over the past seven years. In June, a study supported by Public Safety Canada found that the national average from 2011 to 2015 on this site was slightly higher at $7.69. Meanwhile, a report by the Parliamentary Budget Officer last year estimated that the average black-market gram cost $8.84, though it stated that prices varied considerably across the country.

The researchers commissioned by Public Safety Canada stated that this data has limitations and that this is an area "ripe for future research."

"The current data collection efforts are simply not sufficient for scholars and policy makers to assess the impact of legalization on the behaviour of consumers of cannabis and other substances," the report said.

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Philip Smith, a researcher with Statistics Canada, said using this crowdsourcing site was the only way the agency could estimate the past and current price of cannabis on the black market, but the data will need to be interpreted cautiously. He added that the agency has tentative plans to do four special household surveys in 2018 asking consumers of black-market cannabis about their habits. He said longer-term, community studies would be a good idea, but Statscan's limited budget does not allow for them at this time.

In response to a call for more independent cannabis research, the government-funded Canadian Institutes of Health Research is set to award 10 grants next month of up to $100,000 for year-long projects, with the money becoming available at the beginning of next March. Since the start of last year, CIHR has also approved $6.8-million in funding for 15 different cannabis projects on topics such as mental health and road safety.

David Hammond, CIHR chair in applied public health who teaches at the University of Waterloo, said the federal and provincial governments are doing their best, but are still struggling under the weight of setting up the regulatory system. The CIHR studies receiving funding in January, he says, will likely begin too late to collect meaningful baseline data about the illegal market before next summer.

"It didn't come soon enough. The research wheel doesn't roll that quickly: you got to write your grant; you got to apply; it's got to be reviewed; and then by the time you get the thumbs up, guess what? It's July, 2018, and the baseline is gone," he said

Dr. Hammond and public-health expert M.J. Milloy, who are doing their own separate studies with customers who buy illegally online and in person at dispensaries, argue that Statistics Canada's approach won't paint a fully accurate picture. That's because these methods rely on people voluntarily disclosing their cannabis use to the government, which has been in charge of prosecuting people for using the substance.

Dr. Milloy, an infectious-disease epidemiologist who is studying the therapeutic effects of cannabis at the BC Centre on Substance Use, said community-based studies that follow users over years are needed to fully grasp the reasons people will keep avoiding the legal market.

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Dr. Milloy said preliminary findings from a continuing long-term study found that many of the 200 customers of Vancouver's dispensaries are patients who say they were driven away from Health Canada's mail-order system for medical cannabis because it was too hard to access.

On average, these people spent $200 a month at these shops for products they said help them combat anxiety (50 per cent), depression (41 per cent) and sleep disorders (39 per cent).

Dr. Milloy said he is looking for funding to expand this study to Toronto and Montreal, which will have public retail models for legal cannabis, as opposed to the mix of private and government outlets expected in B.C.

Bureaucrats in Washington and Colorado have lamented that their states could have collected better statistics and information on the drug before they rolled out the legalization of recreational cannabis.

In California, where voters in the past general election passed Proposition 64, legalizing recreational cannabis, authorities are rushing to open a brand new market by the start of next month.

Daniele Piomelli, director of a new institute for non-medical cannabis research at the University of California Irvine, said his state has committed to funding $100-million in new cannabis research at state universities over the next decade. But California won't have as much baseline data as Canada, he said.

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"Canada has a little bit more of a rational system and we're really looking forward to working with you guys."

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